Bill Calfee
Gun Fool
Over lapping a chambered barrel....
CYA accuracy fool friends:
Over lapping a chambered barrel....
I hope I can put this so you folks may understand it...
A lap can not come out of the bore between strokes......I think it should be obvious why.
Therefore..............
Some length of the lap stays in the bore, both at the breech end and muzzle end.
Now this is the part that can be difficult to grasp...as well as to explain.
The bore, where the lap stays in it, does not receive the cutting action of the part of the lap that stays in the bore.
And this is a confusing part, that complicates things..
___________________________
There's been about a five minute pause, here, between the above sentence and this next one, while I attempt to find the right words.....
________________________________________
The length of the bore, where the lap stays in, receives a diminishing degree of cutting action from the part of the lap that stays in the bore....
And by the way.....
The length of the lap that stays in the bore varies, of course, unless one used some sort of stop on the lapping rod....
Which we do not want to do when we lap.
This "tapered" restriction which takes place at both ends of the bore, is of course a benefit at the muzzle...
But................
It kills accuracy when at the breech.....
This is the problem I caused when I de-glazed Jimmy Jack.....
I got a little too fancy..........
Knowing better...........
And left a slight restriction right in front of the leade.......which can be felt when slugged.....
Oh, it's slight......but at today's level of accuracy there can't be any restriction in the bore at the breech end, no matter how slight....
This "slight" restriction turns a 2400 and up barrel into a 2300 and down barrel, which Jimmy Jack currently is.
Your pistol fool friend, Bill Calfee
_____________________
PS:
When I get Jimmy Jack back to re-lap him, I'll use a couple of lapping tricks that may, or may not, work.
They probably won't......but I have to try.....
If I had any sense I'd cut .750" off the breech end of the barrel, then re-chamber it....
Which would take me past the restriction.....
But I've decided to try the lapping first......
And if it doesn't work, I can then cut the barrel back and re-chamber it.....
But................
Unless I pull a rabbit out of the hat, and someway create a miracle, this barrel will not be the one that stays on Jimmy Jack.....
If I wind up having to cut and re-chamber this barrel, I'll put it on something else.....or make a slave barrel out of it...
CYA accuracy fool friends:
Over lapping a chambered barrel....
I hope I can put this so you folks may understand it...
A lap can not come out of the bore between strokes......I think it should be obvious why.
Therefore..............
Some length of the lap stays in the bore, both at the breech end and muzzle end.
Now this is the part that can be difficult to grasp...as well as to explain.
The bore, where the lap stays in it, does not receive the cutting action of the part of the lap that stays in the bore.
And this is a confusing part, that complicates things..
___________________________
There's been about a five minute pause, here, between the above sentence and this next one, while I attempt to find the right words.....
________________________________________
The length of the bore, where the lap stays in, receives a diminishing degree of cutting action from the part of the lap that stays in the bore....
And by the way.....
The length of the lap that stays in the bore varies, of course, unless one used some sort of stop on the lapping rod....
Which we do not want to do when we lap.
This "tapered" restriction which takes place at both ends of the bore, is of course a benefit at the muzzle...
But................
It kills accuracy when at the breech.....
This is the problem I caused when I de-glazed Jimmy Jack.....
I got a little too fancy..........
Knowing better...........
And left a slight restriction right in front of the leade.......which can be felt when slugged.....
Oh, it's slight......but at today's level of accuracy there can't be any restriction in the bore at the breech end, no matter how slight....
This "slight" restriction turns a 2400 and up barrel into a 2300 and down barrel, which Jimmy Jack currently is.
Your pistol fool friend, Bill Calfee
_____________________
PS:
When I get Jimmy Jack back to re-lap him, I'll use a couple of lapping tricks that may, or may not, work.
They probably won't......but I have to try.....
If I had any sense I'd cut .750" off the breech end of the barrel, then re-chamber it....
Which would take me past the restriction.....
But I've decided to try the lapping first......
And if it doesn't work, I can then cut the barrel back and re-chamber it.....
But................
Unless I pull a rabbit out of the hat, and someway create a miracle, this barrel will not be the one that stays on Jimmy Jack.....
If I wind up having to cut and re-chamber this barrel, I'll put it on something else.....or make a slave barrel out of it...
